What effect does applying coolant have during milling operations?

Applying coolant during milling operations serves multiple important functions, but its primary role is to cool the workpiece and reduce wear on the cutting tool. The milling process generates a significant amount of heat due to friction and the cutting action itself. Excessive heat can lead to thermal expansion, which might distort the workpiece or affect the tolerances, and it can also contribute to tool wear, shortening the lifespan of the cutting tool.

Coolant helps dissipate this heat by providing a cooling effect, thus maintaining a more stable temperature throughout the cutting process. Additionally, it reduces the friction between the cutting tool and the workpiece, which not only helps in prolonging the life of the tool but also improves the surface finish of the machined part. This is crucial for ensuring that precision and quality standards are met in milling operations.

The other options, while they may have some relevance in specific contexts, do not capture the primary purpose of coolant in milling as effectively as the correct answer.